Thursday, April 05, 2012

I have been wanting to do something like this for a long time. A couple of years ago, I made a short video of my workflow for an HDR photograph, and I gave it to my students and friends, but didn't share it here on the blog as the file was too large to post. I am working away around that now, and hopefully, I will be able to share a video with you on how I create my HDR's. In the meantime, I thought I would share a few details on what I do in this post...Most bloggers will just tell you...

take five bracketed shots of your scene, merge your shots into an HDR using Photomatix, and then finish off your photograph in Photoshop.

Well, if you are like me, that is not nearly enough info...so, I am going to get into the nitty gritty of what I do so that maybe you can walk away today with a little more info and some pointers on how to create a decent HDR image.

First off, HDR has become hugely popular in the past couple of years. Seems like everyone is creating HDR images these days. There is still a LOT of hate for HDR...I will never really understand the hatred, but to each his own, I guess. I happen to like it. Yes, sometimes an HDR image can look "cartoonish" or "over saturated" or not realistic....ya, so what? It is the artists ' interpretation, and the artist can do whatever he/she wants...you don't have to like it.

My own style has varied over the years with my HDR. When I first starting doing HDR, I was dreadful at it....I look back on my own photos from a couple of years ago, and wonder what the hell I was thinking....but I have since refined my techiques, and I think my HDR's look much better these days, but there is always more to learn...so, what I discuss in this short tutorial is not the end-all technique, but a place to start...as time goes on, my style (and yours) evolves...what I like today may be totally different two years from now. Software and skills also evolve...I often go back and "re-work" an image using more modern software and new techniques that I have learned.

In this tutorial, I will be giving you the details on how I created the photo below...I am not saying this is my best HDR ever (far from it), but it is a good example as it had a few of the common problems that crop up when creating an HDR image, and I will show you how I dealt with those problems.

This is the final image after post processing...I will post it again at the bottom of the post so that you don't have to scroll all the way up again to see it...

First things first....what makes a certain scene a good candidate for an HDR? Well, HDR stands for High Dynamic Range. Which in essence means that scenes which have a large range between its shadows and highlights will make a good candidate for an HDR. If you look at the photo below (my middle exposure from 5 bracketed shots), you will notice the left alley is well lit, where the right alley is deep in shadow. My eye saw everything perfectly exposed. Our eyes have an incredible dynamic range, but your camera does not. It wants to look at one area of the photograph, and expose it perfectly. With just one shot of the scene below, it is near impossible to have every part of the photograph exposed properly. My Leica M9 exposed for the bright areas on the left and the distant right, but when doing so, the shadow areas are way under-exposed. With one shot, the camera did not capture what my eyes saw that day...so what to do? The answer...several shots all shot at different exposures to capture the entire dynamic range of light in the scene. That is the idea of an HDR...we blend those different exposures into one photograph that artificially displays the dynamic range that our eyes see.

How do I take bracketed exposures?

There are actually a few ways to do this. You can manually bracket your exposures by changing the shutter speed, or you can change the aperture and keep your shutter speed constant. However, the latter is not recommended. Why? Well, when you change the aperture, you change the depth of field, and when you blend your exposures together, you will find many areas of your photograph out-of-focus. So, to avoid that, keep your aperture constant and change the shutter speed. What shutter speed to use and how much to change it between exposures will depend on the ambient light available in the scene and the range of light between shadows and highlights. If for example, you are shooting into the sun, there could be a huge range between shadows and highlights....the more the range, the more exposures you will need. I often will shoot between 7 and 9 exposures if I am shooting into the sun. However, most photos are taken with the sun at the side of us or behind us...in these cases, 5 shots separated by one stop each will suffice. For a majority of my HDR's I shoot 5 exposures at -2, -2, 0, +1, +2....so that means two stops below the normal exposure and two stops above and one at the regular exposure. For this particular shot, I exposed my camera for the highlights, and then set up my camera to automatically shoot 5 exposures in aperture priority mode. Most cameras these days will have that "auto" function to take a series of bracketed photos with one push of the shutter. My old Nikon could take a series up to 9 different exposures, but my Leica will only allow a max of 7.

Do I have to use a tripod?

Better to use a tripod to prevent any camera shake and to make it easier to align the images in post. However, a tripod is not always with you and is not always needed. I did use a tripod for this shot because my shutter speeds of my upper two exposures were relatively slow...but many times, the dynamic range is not that great, and all shutter speeds are pretty quick. If this is the case, you can get away with hand-holding you camera (as still as you can).

Below is the middle exposure...you can see the "dynamic range" of light in this photograph...perfect candidate for an HDR...my brightest exposure exposed the shadow areas on the right, but the left side highlights were blown out. The idea is to combine the exposures to have the complete range of light exposed properly like our eye would do...

Ok, so you now have your five exposures in your camera. I usually check to see if I had indeed caught the entire range of light. If not (sometimes you still can't see the shadow areas), I will add a stop or two and re-shoot so that the entire range of light is captured.

By the way, best to shoot in RAW...I always shoot in RAW...you don't want your camera to do any in-camera editing of your images...

I download my photos to Adobe Lightroom....Adobe just came out with LR4, and it is awesome! Photomatix also makes a plug-in for Lightroom that enables you to export your photos right from LR into Photomatix....sure makes your workflow faster. You can find more info for LR HERE, and info on Photomatix HERE...I don't have any connection with either Adobe or HDRsoft (makers of Photomatix), but do really like their products!

I select my photos in Lightroom, and then export them directly into Photomatix. Photomatix then creates the HDR and opens the photo where you can then tone-map your image playing around with the various sliders provided. There are also some pre-sets that you can use. I play with the sliders until I get the most "realistic" look that I can, but this will totally depend on your style and what you like...

Below is the result after Photomatix had blended my exposures and I messed with the sliders...

After you are satisfied with the initial look of your photo from Photomatix, click "save", and if you have the LR plug-in, your photo will be re-imported back into LR...

There are some real problems with the photo above. Many think that once they have finished with Photomatix, the photo is done. Far from it. Have a look above....here are the problems that I see...

Problem 1. Ghosting....see the people in the photograph....they look like ghosts. Need to fix that, and this is what I did. I chose one of my exposures that clearly shows the people near the same spot as the "ghost". I had to use two different exposures...one for the two dudes on the left, and one for the people on the right in the shadows. I then had to match the relative brightness of each exposure so that it matches my HDR....I do this in LR. I just adjust the exposure until it looks relatively the same as the HDR image. I then open each of these images in Photoshop, and use Nik's Color Efex Pro's Tonal Contrast filter to make the people more HDRish looking...I often reduce the opacity of the effect to not overdo it...then I went back to the HDR...duplicated the layer, and moved the new photo I just adjusted below the duplicated layer in photoshop. I selected the two layers and used "auto align" to be sure the two layers were aligned. I then created a mask on the top layer (the HDR). I can now "paint in" the new people by painting in black on the mask...once I painted in the new people, I did the same thing for the people on the right.

Problem 2: The sky. I hate what Photomatix does to skies. Almost 100% of the time, I have to mask back in the sky from one of my exposures. If you look at the sky near the roof on the right, you will see a "halo" effect...this is a dead giveaway for most HDR's, and the one many people neglect to fix. It is actually an easy fix. I just choose the sky I want from one of my five exposures, and move it (like I did for the ghosting) into Photoshop as a new layer where I mask in the sky. For this photo, the sky I used was darker than the sky in the HDR, so I had to be careful masking at the edges of the roof as the darker photo darkened the roof as well.

Problem 3: Color. Photomatix does a great job in blending the photos, but the color is usually very flat as you can see from above, and it will often lack in the blacks. The color adjustments can be done almost entirely in LR...I first grab the black slider and add back some of the blacks, but not too much. I can then change the white balance to either warm up (usually) or cool down the overall white balance. I then go into the individual colors and boost some and reduce others until I get the overall color balance I want. This is totally subjective...no formula...I just play around until I get what I want...

Problem 4: Sharpness. Photomatix usually softens the photo...another giveaway that the photo is an HDR. I use "unsharp mask" in Photoshop to sharpen my photos, and then sharpen again if I am going to make a print.

Other problems that can occur: Although I didn't have a problem with this photo, often you will have some areas either in the shadows or the highlights that are lost or blown out. Again, if this happens, just choose one of your exposures where it got the area right, and mask in those parts.

Here is the final version again...notice the people are no longer ghosts, the sky looks natural, and the buildings have vibrant colors and everything looks sharp...

Hope you enjoyed this tutorial, and hope you learned something....cheers, Scotty

About Me

I don't know what I want to do when I grow up. I have been a helicopter pilot, a SCUBA instructor, a teacher, and a photographer.
I have been in Indonesia for the past 15 years. It has been a great ride so far, and the adventure continues to get better every day.
I hope you enjoy my photos...if you are ever in this part of the world, lets go shooting together...what are you waiting for?